ACLS Practice Test: Video 5 Answers (20 Questions) — Questions and Answers

Question 1: During CPR, PETCO2 remains persistently below 10 mmHg. What does this most strongly suggest?

Tube is in the right mainstem bronchus
Need to improve compression quality (Correct answer)
Excessive ventilation
Hyperthermia

Correct answer: Need to improve compression quality

A low PETCO2 reflects poor cardiac output, so compression quality should be optimized.

Question 2: Which of the following is the recommended oxygen saturation (SpO2) target after ROSC during post-arrest care?

94–99% (Correct answer)
100% (maximum oxygenation)
88–92%
Greater than 80%

Correct answer: 94–99%

Post-ROSC oxygen therapy should target SpO2 of 94–99% to avoid both hypoxia and hyperoxia, which can worsen neurologic outcomes.

Question 3: How long should interruptions in chest compressions last during an endotracheal intubation attempt?

As long as needed for a successful attempt
Under 10 seconds (Correct answer)
Up to 30 seconds
About 60 seconds

Correct answer: Under 10 seconds

Compression pauses for intubation should be kept under 10 seconds.

Question 4: Which method is the most reliable for confirming and monitoring endotracheal tube placement?

Condensation in the tube
Continuous waveform capnography (Correct answer)
Chest wall movement alone
Auscultation over the epigastrium

Correct answer: Continuous waveform capnography

Continuous waveform capnography is the most reliable confirmation and monitoring method for tube placement.

Question 5: When performing bag-mask ventilation during CPR, what is the recommended tidal volume?

1200 mL to ensure deep lung inflation
800–1000 mL for maximum oxygenation
500–600 mL (enough to produce visible chest rise) (Correct answer)
200–300 mL to avoid hyperventilation

Correct answer: 500–600 mL (enough to produce visible chest rise)

Tidal volumes of 500–600 mL, sufficient to produce visible chest rise, are recommended to avoid gastric inflation and barotrauma.

Question 6: A patient is in pulseless polymorphic ventricular tachycardia. How should it be treated?

Unsynchronized high-energy defibrillation, as for VF (Correct answer)
Transcutaneous pacing
Synchronized cardioversion at 100 J
Adenosine 6 mg rapid IV push

Correct answer: Unsynchronized high-energy defibrillation, as for VF

Pulseless polymorphic VT is treated like VF with unsynchronized defibrillation because synchronization is unreliable.

Question 7: After delivering a defibrillation shock, what should be done immediately?

Administer epinephrine before resuming CPR
Resume CPR immediately, starting with chest compressions (Correct answer)
Check the rhythm for 30 seconds to assess response
Check the pulse and rhythm before resuming CPR

Correct answer: Resume CPR immediately, starting with chest compressions

After defibrillation, CPR should be immediately resumed starting with chest compressions to maintain perfusion, with a rhythm check performed after 2 minutes.

Question 8: Which of the following rhythms requires synchronized cardioversion rather than unsynchronized defibrillation?

Ventricular fibrillation
Unstable atrial fibrillation with a pulse (Correct answer)
Pulseless ventricular tachycardia
Asystole

Correct answer: Unstable atrial fibrillation with a pulse

Synchronized cardioversion is used for organized rhythms with a pulse (e.g., unstable AF, SVT, stable VT), while unsynchronized defibrillation is reserved for pulseless rhythms and VF.

Question 9: A pregnant patient in the third trimester develops pulseless VF. How should defibrillation be performed?

Use only synchronized shocks
Use standard energy doses without hesitation (Correct answer)
Use half the standard energy to protect the fetus
Delay the shock until the fetus is delivered

Correct answer: Use standard energy doses without hesitation

Defibrillation energy to the mother does not harm the fetus, so standard doses should be used promptly.

Question 10: What is the recommended first defibrillation dose for a child in pulseless VF?

0.5 J/kg
2 J/kg (Correct answer)
200 J fixed dose
10 J/kg

Correct answer: 2 J/kg

The initial pediatric dose is 2 J/kg, with later doses at 4 J/kg or higher, not exceeding 10 J/kg or the adult dose.

Question 11: Which ECG changes are classically associated with severe hyperkalemia?

Shortened QT with ST-segment elevation
Delta waves and short PR interval
Peaked T waves and a widened QRS complex (Correct answer)
Prominent U waves and flattened T waves

Correct answer: Peaked T waves and a widened QRS complex

Hyperkalemia produces peaked T waves, flattened P waves, and QRS widening that can progress to a sine wave.

Question 12: Which pattern describes Mobitz type I (Wenckebach) second-degree AV block?

Fixed PR with sudden dropped beats
Absent P waves with irregular rhythm
Progressive PR lengthening until a QRS is dropped (Correct answer)
Wide QRS with random P waves

Correct answer: Progressive PR lengthening until a QRS is dropped

Wenckebach shows progressive PR prolongation until a beat is dropped, then the cycle repeats.

Question 13: In ACLS, which ECG finding is a classic sign of right ventricular strain in massive pulmonary embolism?

Delta waves in multiple leads
S1Q3T3 pattern (S wave in I, Q wave and T inversion in III) (Correct answer)
Prolonged PR interval
ST elevation in V1–V4

Correct answer: S1Q3T3 pattern (S wave in I, Q wave and T inversion in III)

The S1Q3T3 pattern (large S in lead I, Q wave and inverted T in lead III) is a classic ECG sign of acute right heart strain seen in massive pulmonary embolism.

Question 14: A patient has a wide-complex tachycardia at 180 bpm with no pulse. What is the correct ACLS intervention?

Adenosine 6 mg IV rapid push
Unsynchronized defibrillation (shock) (Correct answer)
Synchronized cardioversion
Amiodarone 300 mg IV

Correct answer: Unsynchronized defibrillation (shock)

Pulseless wide-complex tachycardia (presumed VT/VF) is treated with immediate unsynchronized defibrillation as part of the pulseless VT/VF algorithm.

Question 15: What is the significance of a prolonged QT interval in ACLS management?

Increased risk of torsades de pointes (polymorphic VT) (Correct answer)
Indicates complete heart block
Indicates hyperkalemia
Is a normal finding requiring no treatment

Correct answer: Increased risk of torsades de pointes (polymorphic VT)

A prolonged QT interval indicates delayed ventricular repolarization, which predisposes to torsades de pointes — a potentially fatal polymorphic ventricular tachycardia.

Question 16: An adult has sinus tachycardia at 138/min with fever and dehydration. What is the appropriate management?

Identify and treat the underlying cause (Correct answer)
Adenosine 6 mg IV push
Synchronized cardioversion
Amiodarone 150 mg IV

Correct answer: Identify and treat the underlying cause

Sinus tachycardia is a physiologic response, so treatment targets the cause rather than the rate.

Question 17: An ECG shows the PR interval lengthening on each beat until a P wave is not followed by a QRS, then the cycle repeats. Which rhythm is this?

Second-degree AV block, Mobitz type I (Correct answer)
Second-degree AV block, Mobitz type II
Third-degree AV block
First-degree AV block

Correct answer: Second-degree AV block, Mobitz type I

Progressive PR prolongation followed by a dropped beat defines Wenckebach (Mobitz I) block.

Question 18: ST-segment elevation in leads V1–V4 most likely indicates ischemia or infarction in which territory?

Anterior wall (LAD territory) (Correct answer)
Inferior wall
Posterior wall
Lateral wall only

Correct answer: Anterior wall (LAD territory)

V1–V4 overlie the anterior wall, supplied mainly by the left anterior descending artery.

Question 19: Which description best fits atrial fibrillation?

Regular rhythm with sawtooth waves
Regular rhythm with a fixed PR interval of 0.16 s
Wide QRS with a twisting axis
Irregularly irregular rhythm with no distinct P waves (Correct answer)

Correct answer: Irregularly irregular rhythm with no distinct P waves

AF shows chaotic atrial activity with no discernible P waves and irregularly irregular R-R intervals.

Question 20: Which rhythm should prompt immediate unsynchronized defibrillation rather than synchronized cardioversion?

Hemodynamically unstable atrial flutter
Atrial fibrillation with rapid ventricular response
Stable monomorphic ventricular tachycardia with a pulse
Ventricular fibrillation (Correct answer)

Correct answer: Ventricular fibrillation

VF has no organized QRS for the defibrillator to synchronize with, requiring unsynchronized (asynchronous) defibrillation at maximum energy.

ACLS Practice Test: Video 5 Answers (20 Questions)

During CPR, PETCO2 remains persistently below 10 mmHg.
What does this most strongly suggest?

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